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In this paper, we explore the possibility of connecting decentralized biogas plants via a pipeline network to terminals that upgrade biogas into biomethane. We present a mixed-integer linear program that forms subnetworks of such plants, decides on suitable terminal locations, and establishes pipeline connections to maximize profit. We apply this model to a real-world scenario in Northern Germany. The results show a much higher total profit for the optimized network compared to the benchmark solutions where each plant upgrades biogas into biomethane on its own. Therefore, plants can increase their profitability by collaborating with other (neighboring) plants. However, the collaboration requires a fair profit-sharing model as network participation is not individually profitable for all plants, especially small ones. • We explore network designs for a profitable upgrading of biogas into biomethane. • We introduce a Mixed Integer Programming model to determine optimal plant networks. • A real-world application for biogas plants in Northern Germany is presented. • Results reveal higher profits for the networks compared to stand-alone upgrading. • Fair profit-sharing mechanisms are important for plant collaborations. [ABSTRACT FROM AUTHOR]

This paper examines the emergence of 1,072 solar initiatives (268 associations and 804 cooperatives operating photovoltaic systems) from 2006 to 2018 in Germany. The study draws on organizational ecology theory to identify factors that influence the likelihood of establishing a solar initiative by investigating the impacts of two opposing effects: legitimation effects and competition effects. We show that the density of medium-scale photovoltaic installations in a district negatively affects the likelihood of establishing a solar initiative, suggesting that competitive dynamics prevail between different market entrants, dampening the emergence of solar initiatives. By contrast, we find that the founding of a solar initiative in a district has a positive effect on the probability of founding other solar initiatives in the same district, confirming legitimacy effects. Further, we show that solar initiatives are more likely to be founded in rural areas, especially in densifying rural areas. • Citizens collectively install PV systems where there are fewer similar systems present. • Initiatives are more likely to emerge in districts with existing initiatives. • Initiatives emerge primarily in densified rural areas. • Enhancing organizational rather than technological knowledge is important. [ABSTRACT FROM AUTHOR]

In this paper, a multi-step framework to design flexible power-to-methane processes is presented. The approach considers all crucial parts of the power-to-methane process, including the renewable energy source. The aim is to provide a design that allows for feasible operation under the fluctuating conditions induced by the renewable energy source at all times. For each part of the process, the operating windows are analyzed and optimized under different site-specific constraints, and recommendations for actions regarding the technical implementations are provided. The impact of the carbon dioxide source is scrutinized, and subsequent scheduling optimization is performed to determine necessary storage capacities. The framework is demonstrated on two carbon dioxide availability scenarios where the renewable energy source is a wind turbine coupled to a polymer exchange membrane electrolyzer that produces hydrogen, which is then converted to methane in a fixed-bed reactor. The results show that the feasible operation of the system strongly depends on the site-specific conditions. In particular, the availability of carbon dioxide impacts the flexibility of the methanation reactor. When the stochiometric ratio between hydrogen and carbon dioxide cannot be sustained, the operating window of the reactor deteriorates significantly. However, it is shown that appropriate integration and scheduling of storage capacities debottlenecks the reactor and enables the utilization of all electricity generated by the wind turbine. • A framework for the design of flexible power-to-methane systems is introduced. • Optimization approaches for each step of the framework are provided. • A dynamic optimization approach for storage integration is given. • The impact of the carbon dioxide provision flexibility is investigated. • The framework is tested in a case study with an onshore wind turbine in Germany. [ABSTRACT FROM AUTHOR]

Organic food contributes to environmental sustainability and is becoming increasingly popular worldwide, although it is generally more expensive than conventionally produced food. Rather different sets of values and motivations are driving consumers' purchase intentions in mature compared with emerging organic food markets. To inquire about similarities and differences in consumers' motives our qualitative, comparative study employs a series of in-depth interviews with organic-food-store clients in Germany and Thailand from February to May 2021. The analysis applied means-end chain (MEC) theory to map the mental decision-making processes. Results were interpreted and compared referring to the Schwartz Theory of Basic Human Value (STV). The findings show a rather similar values base of both samples in terms of the relevance of 'quality of personal life' and 'personal well-being'. Substantial differences emerged in the Germans high emphasis on the values 'health of environment' and 'social responsibility' which were absent in Thailand, while Thais put great importance on the 'responsibility for family'. Focusing on the five most important values in each country, we conclude a more personal-focused value system in Thailand, respectively a rather social-focused one in Germany. This paper contributes to the literature as it is one of the few qualitative studies on organic food purchase intention using MEC and STV and the first one conducted in Thailand. The findings provide valuable insights for producers and marketers to better address German and Thai consumers' needs to influence their purchase intention towards organic food consumption. • Germans have a more social-focused value system when buying organics. • Thais have a more personal-focused value system when buying organics. • Similar values base: 'quality of personal life' and 'personal well-being'. • Germans emphasize 'health of environment' and 'social responsibility'. • Thais prioritize 'responsibility for family'. [ABSTRACT FROM AUTHOR]

Finding alternative phosphorus sources is imperative to address negative environmental and societal impacts caused by its current inefficient use. However, the direct use of phosphorus in sewage sludge in agriculture is controversial. This paper uses Denmark, Germany, and Spain as case examples to assess relevant legislation and boundary conditions in agricultural production to identify opportunities and barriers for the utilisation of recycled phosphorus from wastewater in agriculture on a regional level. Only five out of 22 phosphorus recycling technologies considered were in full compliance with legislation across all three countries, and these five were then assessed for their potential to supply phosphorus to major crops within countries. We considered the application of technologies across four scenarios: 1) struvite; 2) vivianite as iron supply; 3) vivianite for calcium phosphate precipitation; and 4) ashes for calcium phosphate precipitation. The most suitable scenario identified for Denmark was vivianite for calcium phosphate precipitation, whereas in Spain vivianite as iron supply was identified as most suitable, and ashes for calcium phosphate in Germany. We found that in 2018, the potential phosphorus supply from recycling technologies was on average 0.38, 0.29 and 0.05 kg of phosphorus per capita for Danish, German, and Spanish regions. These quantities could meet 9.1, 21.7, and 10.0 percent of the phosphorus required to produce major cereals in each country (specifically wheat, barley, and rye). Given current legal constraints, wastewater treatment plant connections and agronomic context, the potential contribution of recycled phosphorus is non-negligible in many sub-national regions. Still, to access the full potential of phosphorus circularity clear product specifications and transport and logistics among regions will be necessary. [ABSTRACT FROM AUTHOR]

Tackling societal challenges relating to sustainability requires both an understanding of the underlying complex socio-ecological systems and participation of scientists as well as relevant stakeholders, such as practice experts, decision makers, and citizens. This paper introduces the Decision Theatre Triangle, a method which combines empirical information, mathematical modelling and simulation, and a format for dialogue between scientists and stakeholders. While it builds on previous Decision Theatre work, the new structuring into these three elements emphasizes what is needed for setting up a Decision Theatre for a given challenge. Based on experience with a specific example – sustainable mobility in Germany – it is argued that agent-based models are particularly suitable for Decision Theatres and that the method is useful not only for decision support but also for science communication and co-creation of a deeper knowledge of the system under discussion. As a step towards facilitating a broader use of the Decision Theatre Triangle method, the paper then sketches research needs for each of its three elements, with a focus on mathematical modelling and simulation. [Display omitted] • The Decision Theatre Triangle combines data, models, and stakeholder dialogues. • It enables decision support, science communication and co-production of research. • Agent-based modelling shows benefits in the Decision Theatre Triangle method. • Setting up Decision Theatre Triangles for societal challenges needs model structures. [ABSTRACT FROM AUTHOR]

With its strong ties to the European Union, Germany is well-positioned to assist many countries achieve sustainability goals. Therefore, the main objective of this paper is to examine how renewable energy intensity and renewable energy share improve environmental sustainability, the load capacity factor (LCF) in Germany from 1970 to 2018. To this end, the study uses the autoregressive distributed lag model, with the effects of the Kyoto Protocol included as a dummy variable. The study contributes to the literature by considering and testing for the first time the impact of renewables on the LCF in terms of intensity and share for Germany. The empirical results show that (i) economic growth lowers the LCF faster in the early stages of economic development than in later periods; therefore, the environmental Kuznets curve hypothesis is valid in Germany. (ii) A 1% upsurge in renewable energy intensity has no statistically significant effect on the LCF, while a 1% rise in the share of renewables in the total energy mix increases LCF by 0.48%. (iii) A 1% rise in urbanization reduces the LCF by 6.52%. (iv) A 1% augment in human capital enhances the LCF by 3.49%. These outcomes suggest that the German government should use human capital development and increasing the share of renewable energy as policy instruments to achieve the sustainable development goals. [Display omitted] • The EKC hypothesis is valid for Germany. • Renewable energy intensity has no influence on the load capacity factor. • A higher renewable share in the energy mix is associated with an improvement in LCF. • Human capital plays a key role in solving environmental challenges. • The urbanization process has a devastating effect on the environment. [ABSTRACT FROM AUTHOR]

To comply with the European Green Deal, decarbonization of transportation is decisive, especially a shift towards more sustainable transportation services is essential. Due to the tripartite nature of sustainability (society, environment and economy), multiple interrelated criteria are part of the sustainability assessment of transportation services. Discovering these interrelations between criteria to anticipate conflicts and integrate them appropriately into multi-criteria analysis is important for ranking urban transportation services. This paper presents a novel, two-folded methodology for assessing the sustainability of different urban transportation services. First, integrative structural modeling with polarity (ISM-P) is used for universally identifying sustainability criteria interrelationships and weighting them. Second, the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE) method is applied to a sustainability assessment of five specific urban transportation services (public and sharing). In conclusion, applying the methodology to the example of urban transportation services in the Ruhr region, the importance of public transportation as the most sustainable alternative is proven. • A holistic method for sustainability appraisal with dependent criteria is presented. • Urban transportation sustainability is assessed using 12 multi-dimensional criteria. • Demand and operating cost, as well as occupancy and operating cost diverge. • Combining multiple services increases overall transportation sustainability. [ABSTRACT FROM AUTHOR]

Integrating large amounts of electrolyzer capacities poses particular challenges for grid operators along the entire hydrogen value chain. This research examines how hydrogen production capacities that support the decarbonization of German industrial sectors impact the electricity transmission grid. The operation of electrolyzer capacities and the production of green hydrogen result in increased electricity demand that stresses the power grids beyond conventional electricity load levels. The question arises to what extent electrolyzer capacities cause additional grid congestion and how flexible operation of electrolyzers can contribute to efficient management of future power grids. A scenario framework is created, differing in the decarbonizing strategy of industry sectors, operation mode of electrolyzers, and penetration levels of electrolyzer installations for a market projection of the future European electricity system. Model-based research is performed by applying a fundamental electricity market and congestion management optimization model of the European electricity systems for the set of scenarios. Results of the model-based investigation highlight the importance of integrating electrolyzer capacities into congestion management practices, primarily if corresponding decarbonized industries feature a more distributed allocation throughout Germany, such as the chemical, paper and printing industries. The findings of this work provide policymakers, system operators, and regulators with meaningful insights for designing future congestion management frameworks. [ABSTRACT FROM AUTHOR]

Many studies have analysed the environmental impact of vegan, vegetarian, or reduced meat diets. To date, literature has not evaluated how diet shifts affect environmental impacts by utilising portfolios which reflect personal nutrition preferences. Further, changing diets could alter the available land for non-food uses. This paper defines novel diet portfolios to outline alternative diet transitions and choices within the population and finds their effect on greenhouse gas (GHG) emissions, primary energy use, and land use in Germany. The aim of this study is to capture how these diet shifts affect land availability and increase the options for land-based climate change mitigation strategies. To do so, a contextualisation is made to compare the use of freed-up land for afforestation or biomethane production (with and without carbon capture and storage). The investigated diet portfolios lead to a reduction of the investigated impacts (GHG emissions: 7–67%; energy use: 5–46%; land use: 6–64%). Additionally, afforestation of freed-up land from each diet portfolio leads to further emission removals of 4–37%. In comparison, using the land to produce energy crops for biomethane production could lead to 2–23% further CO2-eq emission reductions when replacing fossil methane. If biomethane production is paired with carbon capture and storage, emission abatement is increased to 3–34%. This research indicates various short-term pathways to reduce GHG emissions with portfolio diet shifts. Utilising freed-up land for climate change mitigation strategies could prove essential to meet climate targets, but trade-offs with, e.g. biodiversity and ecosystem services exist and should be considered. • Diet portfolios are used to represent realistic population diets. • Diet portfolios include a mixture of 12 different diets. • GHG emissions decrease by 67% if the population adopts a Vegan diet. • Afforestation removes almost double the emissions compared to biomethane. • BECCS has similar GHG abatement to afforestation. [ABSTRACT FROM AUTHOR]

High-efficiency buildings do not only save energy but also have multiple further impacts or co-benefits. These impacts are often excluded from the policy evaluation partly because their quantification and integration into cost-evaluations have challenges. Thus, the purpose of this paper is to develop a method to quantify labour productivity which is one of the key multiple impacts, as well as demonstrate the use of the method for calculating the productivity impacts of high-efficiency buildings. The paper uses Germany and Hungary as examples to conduct the quantifications. The result of the study shows that high-efficiency buildings can result in substantial health and labour productivity benefits. Concretely, a German worker can gain 5.2 productive days a year, while a Hungarian 2.2 days by avoiding sick days, after living in high-efficiency buildings. Similarly, through high-efficiency retrofits or high-efficiency new constructions in the tertiary building sector, German and Hungarian workers can gain 2.4 and 1 productive days a year, respectively, by avoiding sick days. The monetary equivalent of the total number of days gained would be as high as 337 million and 7 million Euros/year only from the residential building sector, and 398 million and 3 million Euro/year from the tertiary building sector for Germany and Hungary respectively. In addition to the productive workdays gain, by avoiding mental stress, the German and Hungarian workforce can gain 95 and 2 million Euro respectively in a year by improving work performance from working in high-efficiency tertiary buildings. Furthermore, this paper shows that along with more workdays and improved work performance, both Germany and Hungary can gain 1870 and 3849 healthy life years/million population which is equivalent to 277 and 134 million Euros per year respectively. The findings of this study would provide a strong motivation to the policymakers to design policies that promote construction and renovation of buildings at the passive-house or NZEB standards. The substantial productivity impacts of high-efficiency buildings can be an entry-point for the policymakers as any policy that promote high-efficiency buildings would fit in well in the multi-objective policy framework of the European Union. • High-efficiency buildings can obtain substantial health and productivity benefits. • A novel methodological approach to quantify labour productivity is demonstrated. • High-efficiency buildings result in more active workdays by minimizing health risk. • Substantial monetary gain can be obtained from the productivity benefits. • Findings can motivate policies to implement more high-efficiency buildings. [ABSTRACT FROM AUTHOR]

Small and medium-sized enterprises (SMEs) are said to engage significantly less with corporate sustainability (CS) than their larger peers, because they are more reluctant to voluntarily engage in CS beyond regulatory thresholds. However, the mechanisms for changing the reluctance of SMEs with regard to CS are poorly understood. By drawing on self-determination and stakeholder theory from a social proximity perspective, this paper argues that stakeholders play a key role in influencing the controlled CS motivation of SMEs, and that SMEs will consider the claims of 'proximate' stakeholders as being more salient than 'distant' regulatory pressure, with the latter even potentially exercising a negative effect on SMEs' controlled CS motivation. The hypotheses are empirically tested using survey-based data from a sample of 344 privately-held SMEs operating in Germany and Austria. Results of the structural equation model confirm that 'proximate' employee and community pressure reduces controlled CS motivation and ultimately increases overall CS performance, whilst 'distant' regulatory pressure has precisely the opposite effect, ultimately reducing the CS performance of SMEs. These findings help to clarify that the close attachment of SMEs to their employees, and their deep embeddedness in the local community might be important catalysts with regard to CS improvements of SMEs, whilst regulatory pressure reduces their willingness to engage in CS, since this is often perceived as an unfair, demotivating, external imperative, which compromises their self-determination. Lastly, theoretical and managerial implications are provided. [Display omitted] • We analyze the influence of stakeholder pressure on corporate sustainability (CS). • Social proximity (close vs. distant) is a driver of stakeholder salience in SMEs. • Close employee and community pressure reduces controlled CS motivation. • Distant regulatory pressure increases controlled CS motivation. • Policy-makers should be cautious to apply regulatory pressure to spur CS. [ABSTRACT FROM AUTHOR]

Prosuming combines energy production and consumption on a decentralised level and can contribute to expanding renewable energies and integrating intermittent energy in a decarbonised energy system. This is only one way that conventional electricity consumers can become active agents in electricity systems, but the current literature lacks a comprehensive typology of this field. Furthermore, the literature on prosuming focuses on households and largely neglects organisations. Addressing these two gaps in the literature, this paper first suggests a typology of eight archetypes that encompass electricity production, demand management, and storage as dimensions. Second, it maps the decision-making process for prosuming infrastructure in small and medium-sized organisations based on 14 in-depth interviews from Germany. To better understand the implementation processes of prosuming infrastructure and to identify critical success factors for organisations to become active electricity agents, it outlines a comprehensive collection of motives, drivers and barriers that are shaped by the organisational context and play a significant role when organisations become energy prosumers. [ABSTRACT FROM AUTHOR]

Plastic pollution has become a major global risk. The European Union (EU) obligates all member states to implement measures according to the waste management hierarchy, with the highest priority given to waste prevention and reuse. Currently, several policies tackle the plastic crisis, while effective measures for prevention are hardly introduced. Moreover, approaches are rarely tailored to individual consumers' needs for reducing plastic waste. This paper is the first to collect and structure stakeholder knowledge on measures that enable consumers to use plastic more sustainably and, in particular, to prevent the generation of new plastic waste. The present study explores perspectives of 28 selected German stakeholders from the political, economic, civil and scientific sector. Written expert interviews with open questions captured stakeholders' perceptions of the plastic problem and their approaches to enabling consumers to reduce plastic packaging for food and beverages. Results showed that the interviewed stakeholders did not point out consumers as the most important agents for change, but considered all societal agents responsible for implementing a wide range of consumer-enabling measures. The analysis revealed six groups of suggested measures, the most predominant ones being (1) the creation of alternatives for consumers and (2) political measures. Further suggested measures were (3) communication and awareness raising, (4) change in consumer behavior, (5) technical innovation and development, and (6) networking with other stakeholders. Based on our empirical results, we derived nine recommendations for action on three levels of the waste management hierarchy: prevention, recycling and disposal. • Plastic waste prevention is not implemented as prioritized by European legislation. • The current policy framework hardly enables consumers to reduce plastic waste. • Twenty-eight stakeholders were interviewed about such measures to enable consumers. • Suggested measures vary greatly among the sectors of interviewed stakeholders. • Derived recommendations for action aid the implementation of suggested measures. [ABSTRACT FROM AUTHOR]

Oxy-combustion is a feasible CO 2 capture method in the power and heat generation sector. This paper aims to propose a methodology for assessing two oxygen production technologies for small-scale oxy-combustion units: i) two-bed pressure swing adsorption (PSA), and ii) liquid oxygen delivery (LOX) for any local conditions, including the greenhouse gas (GHC) footprint for the oxygen that is produced. An analysis of PSA technology and LOX technology was carried out for the Czech Republic and for Germany, where the electricity, labor costs, and greenhouse gas (GHC) emission factors of electrical power differ considerably, but the equipment costs are similar. The analysis always has to be based on local prices, especially on the electricity price that is available for consumers operating PSA units and the price for liquid oxygen delivery, and also GHC emission factors for the electric energy produced in a given area or country. Depending on the local conditions, we may reach completely different conclusions concerning the technology that will be chosen for oxygen supply. • Two oxygen sources for small oxy-combustion units were economically analysed. • These sources were assessed: i) PSA technology, and ii) LOX delivery technology. • The operating costs are affected by local electricity prices and LOX price. • The electricity cost varies country from country and depends on electricity take-off. • Depending on the local conditions completely different conclusions can be obtained. [ABSTRACT FROM AUTHOR]